This invention relates to an improved hockey stock for use in playing ice and street hockey.
The standard design for a hockey stick comprises an elongated handle or shaft portion and a single, generally rectangular blade portion disposed at approximately a 90-degree or slightly greater angle with respect to the handle. These sticks are commonly made of wood, plastic, or composite materials such as fiberglass. It has been common to use blades that are curved in a forwardly concave direction to improve puck control and forward shooting ability. The disadvantage of a curved blade, however, is that the curvature adversely affects backhand shots because the puck may slide or be deflected off the convex rear surface instead of being squarely hit in the desired direction of travel.
Recently, this problem has been addressed by the development of dual-blade hockey sticks comprising a split or bifurcated blade in which the front (forward-facing) blade toe is forwardly concave and the rear (rear-facing) blade toe is substantially flat. Such dual-blade hockey sticks are described in U.S. Pat. Nos. 4,570,932 to George R. Cote and 4,793,613 and 4,799,682 to Owen P. Hughes. The disclosures of these patents are incorporated herein by reference.
The Cote patent utilizes a wedge of a relatively soft material positioned at the tip of the blade in order to create a winged tip resulting in a forward surface curvature while retaining a more or less flat rear surface. The Hughes patents describe a dual-blade hockey stick in which there is no separating spacer or wedge between the "toes" of the blade (as in the Cote stick) thereby permitting the forward and rear toes to flex independently.
Most ice hockey blades are laminated with wood and/or fiberglass. The individual laminae or plies are held together with some type of adhesive bond. These adhesive-type bonds work fine when supporting in-plane shear loads but not the inherent tensile load associated with the dual-blade sticks, especially where the forward and rear toes flex independently as in the Hughes hockey stick. On the other hand, street hockey blades are typically molded in plastic as one material.
For both laminated and molded constructions, however, an open V-shaped blade is extremely susceptible to fracture. Out-of-plane (plane of blade) or through-the-thickness tensile stresses cause fracture by the formation of cracks or delaminations between the separate blades originating near the root of the V-joint and propagating towards the heel. A fulcrum effect was found to exist in the vicinity of the V-joint. In other words, displacement of points located before the root would be opposite in sense from those located beyond the root. Blade forces resulting from slapshots, backhand shots, and so forth, induce out-of-plane tensile stresses localized in the vicinity of the root. These detrimental tensile stresses are an inherent characteristic of the bifurcated blade geometry and exist in both laminated (ice) and molded (street) hockey blades.
Indeed, recent experience with the existing dual-blade hockey sticks has confirmed that in use these sticks have a relatively short and unsatisfactory playing life. Stresses and strains generated by repeated striking of the hockey puck, other players' sticks, the ice (or ground), and so forth rapidly lead to stress fractures at and behind the point of bifurcation or crotch of the dual blade leading to eventual separation and premature failure.